Electric safety switch



July 2 1940 R. A. MILL-ERMASTER Y 2,206,107

aLncTnIc SAFETY s'wn'ca` Filod April 10, 1939 2 Sheets-Sheet 1 WMM 'O4 Wssmwm @j MKM i www R. A. MILLERMAsTi-:R 2,206,107

ELECTRIC SAFETY SWITCH Filid April l0, 1939 2 Sheets-Sheet 2 .f -uo "l" July-2, .1940.

Patented July 2, 1940 UNITED STATES 2,206,101 ELEo'raro SAFETY SWITCH Ralph A.

Millermaster, Milwaukee, Wis., assigner to Cutler-Hammer, Inc., Milwaukee, Wis., a corporation of Delaware Application April 10, 1939, Serial N0. 267,053

18 Claims.

This invention relates to improvements in electric safety switches. The invention relates more particularly to a fuseless main switch of the front-operated push-pull type.

A primary object of the invention is to provide an improved and simplied form of fuseless main switch of the front-operated type.

Another object is to improve the details of construction and arrangement of the parts and the operation of fuseless main switches of the aforementioned type.

Another object is to provide an improved and simplified arrangement of the switch contacts with respect to branch circuit fuse socket contacts associated therewith.

Another object is to provide a combined pushpull fuseless main switch and branch circuit service control device having improved and simplifled means for removably attaching the deadfront insulating plate within the casing.

Another object is to provide a novel form of sheet metal casing for the service control device to provide for alternative association therewith of a screw-attached cover member to adapt `the casing for flush mounting or a hinge-attached cover member to. adapt the casing for surface mounting.

Another and more specific object is to provide stationary and movable switch contacts of novel form, and a novel form of insulating actuating member for the latter.

Another object is to provide novel resilient means tending to insure movement of the insulating actuating member to one or the other lof its extreme positions.

Another object is to provide a service control device of the aforementioned character having means of novel form to ail'ord grounded neutral connections.

Another object is to provide elements of novel form upon the casing cover and the insulating actuating member to provide for sealing of the latter in its circuit interrupting position.

Other objects and advantages of the invention will hereinafter appear,

The accompanying drawings illustrate a preferred embodiment of the invention, with alternative forms of cover members to be employed with the casing; it being understood that the embodiment illustrated is susceptible of modification in respect of certain details of construction thereof without departing from the vspirit and scope of the appended claims.

In the drawings, v

Figure 1 is a fragmentary top' plan view of a service control device as constructed in accordance with my invention, the hinged cover member being shown in open position; and the major portion of the dead-front insulating plate being shown in dotted lines.

Fig. 2 is a fragmentary sectional view, on the line 2--2 of Fig. 1, the hinged cover being shown in closed position, and the insulating actuating member of the switch being shown in its inner extreme position to, provide for interruption of the controlled branch circuits; the alternative form of cover to provide for ush mounting of the casing and the means for attaching said cover to the casing being shown by dotted lines.

Fig. 3 is a sectional view, on the line 3-3 of Fig. 1, Vwith the hinged cover shown in closed position; and the alternative form of cover and certain of the attaching screws therefor being shown in dotted lines.

Fig` 4 is a sectional view, on the line 4-4 of Fig. 1, showing the insulating base and certain of the switch parts and fuse socket contacts supported thereby.

Fig. 5 is a perspective view of a portion of the sheet metal cover for the casing, illustrating theslotted depression in the cover and the form of the integral perforated lug which provides for sealing of the switch actuator in its circuit interrupting position, and

Fig. 6 is a perspective view of one of the insulating arc snuing members associated with the stationary and movable contact elements of the switch.

l Referring to the drawings, the 'numeral I0 designates a base adapted to be produced by a straight-line molding operation from any suitable insulating material. The base I0 as shown herein isv composed of unglazed gray porcelain, but it is to be understood that other insulating materials having the required strength, and insulating and heat resisting characteristics may be employed Aif desired.v Thus I may employ a molded Bakelite base, in which event, as is well understood by those skilled in the art, the base may be additionally recessed in various areas to reduce the weight thereof while maintaining thesame of adequate strength,

Base IIl isrecessed as shown at II, said recess preferably being in the form of a passage extending therethrough from front to rear. That portion of passage Il opening to the upper surface I2 of base I0 is so dimensioned as to receive with a free sliding fit the full width portion of a at insulating plate -I3,the lower end portion I4 of said plate being of reduced width, and the lower end portionvIS of passage II (Fig. 3) being of similarly reduced width, while freely accommodating portion IA. Plate I3 is thus provided with horizontal shoulders I6 and II which coopcrate with the respective base shoulders I8 and I9 topositlvely limit the degree of inward movement of plate I3 within said passage.

Plate I3 is provided along its longitudinal center line (Fig. 3) with a relativelynarrow slot 2l which extends from a point only slightly above the upper surface I2 of base lll (when plate i3 is in its inner extreme position) to a point adjacent to the lower end of portion i4 of said plate. The lower end portion 2l of slot 2li is preferably slightly enlarged, as shown, toprovide proper clearance for a resilient double-inclined cam member 22, the structure and function of which will be more fully described hereinafter. Extending transversely through slot 20 is a second flat insulating plate 23, of the form best illustrated in Fig. 2, plate 23 having laterally extending integral lugs 24 and 25 adapted to seat within correspondingly shaped recesses in base I6.

Base I is provided in its upper surface with recesses to accommodate the heads of a pair of bolts 26, which heads overlie the aforementioned lug portions 24 and 25 of plate 23 to clamp the latter in position, a metal washer 21 being preferably interposed between each bolt-head and its associated plate lug, as shown in Fig. 2. The Shanks of bolts 26 penetrate corresponding passages provided in base I0 and have threaded engagement with nuts 28 located in recesses countersunk from the lower face of base I0.

Plate 23 as thus attached to base I0 preferably has its upper edge in a plane fiush with the upper surface I2 of said base, and the lower edge 29 (Fig. 2) of plate 23 is positioned for engagement by the lower end wall of portion 2I of slot to positively limit the degree of upward movement of plate I3. As shown in Fig. 2, the aforementioned resilient double-inclined cam member 22 is provided with a hooked upper end 30 which cooperatively engages a correspondingly shaped integral portion of base I0, whereby downward displacement of said cam member is prevented. The aforementioned lug of plate 23 overlies said hooked end 30 of cam member 22 to prevent upward displacement of the latter; and said cam member 22 is further provided at 3l with a bend or bulge to be engaged by the side edge of plate 23, whereby bodily oscillatory movement of said cam member is prevented.

As shown in Figs. 2 and 3 the arrangement is such that the portion 32 of plate I3 below portion 2| of the slot 20 is of substantially square form in transverse cross section; whereby in the relative positions of the parts as illustrated the lower portion of the double-inclined cam 22 engages the left-hand upper corner or edge (Fig. 2) of said portion 32 to yieldably resist initial upward movement of plate I3." When, during upward movement of plate I3, the left-hand lower corner or edge Aof portion 32 passes the apex of the double-inclined cam 22, the upper portion of said cam will act upon said edge to assist in effecting, or tend to effect, completion of the movement of plate I3 to its extreme upper position. Cam 22 acts in the reverse manner with respect to portion 32 of plate I3 to yieldably resist initial downward movement of the latter and to assist in effecting extreme downward movement thereof.

Plate I3 is provided on opposite sides of slot 20 with a pair of substantially rectangular openings 33 and 34 (Fig. 3) to provide for attachment to said plate of a pair of like contactors 35, preferably formed of copper strips. As best illustrated in Fig. 3 each contactor 35 has its upper or connecting portion located within and substantially spaced from the upper edge of one of said plate openingsl 33 or 34, whereby possible coating of the plate surfaces above the contactor will have no deleterious arc-maintaining characteristics. 'I'he arms of each contactor are arranged on opposite faces of the plate, and the reasomo? duced lower end portions of said arms are bent inwardly toward each other over the respective plate shoulders I6 and l1 aforementioned. Contactors 35 are therefore constrained to move in a direction and to a degree corresponding to the direction and degree of movement of plate I3.

For cooperation with contactors 35 I provide two pairs of stationary contact elements, the elements of each pair being respectively arranged on opposite sides of plate I3. Thus as shown in Fig. 1 I provide four ledges offset inwardly from the upper surface I2 of base I0, said ledges being located in a common plane, and one pair of said ledges being better illustrated in Fig. 4. Upon one ledge of each pair is seated the ilat portion 36 of a combined stationary contact and wiring terminal member, each portion 36 being secured in position by a screw 31 the shankof which passes upwardly through base I0 and through a tapped opening in said portion, and the head of which screw is accommodated in a countersink or recess in the lower face of the base. The outer extremity of portion 36 is of reduced width and is formed to provide a head 38, and portion 36 is of still further reduced width at an intermediate point in its length to form a neck 39 (Fig. 4), which is adapted to t rather closely between the inner side walls of a tubular steel member 40 of substantially rectangular form in transverse cross section. Y

As shown in Fig. 4 base I Il is recessed below neck 39 just sufficiently to accommodate the lower portion of member 40, whereby accidental displacement of the latter is prevented. Member 40 is provided in its upper end with a tapped opening to accommodate the steel clamping screw 4I of relatively large diameter, thus providing a so-called solderless connector for one of the line wires to be associated with the switch. The solderless connector just referred to may be of the character described and claimed in my co-v pending application, Serial No. 261,527, filed March 13, 1939.

Formed integrally with portion 36 and bent upwardly at substantially a right angle thereto is a resilient arm 42 a portion 43 of which is oifset inwardly toward plate I3 to provide a contact area, and the upper end or tip of which arm is bent or flared outwardly away from plate I3, as shown at 44 in Fig. 4.

'I'he other stationary contact element of each pair comprises a member comprising a at portion 45 secured to an inner ledge as by means of a screw 31 (Fig. 4) in a manner similar to the portion 36 aforedescribed. Base l0 is provided in its .upper surface with a pair of approximately cylindrical recesses 46 and 41 which are respectively adapted to accommodate center and screw shell fuse socket contacts, for cooperation with plug or branch circuit'fuses (not shown) of usual form. Each of the center contacts of said fuse sockets comprises an integral upwardly offset extension 48 of one of the fiat portions 45,-base I0 being preferably provided with bosses underlying the center contacts 48 to limit the degree of inward displacement of the latter; one of said bosses being shown at 49 in Fig. 4. Formed integrally with and bent upwardly at substantially a right angle to the respective portions 45 are arms 50 having intermediate portions 5I offset inwardly toward plate I3 to provide contact areas, and outwardly bent or flared tips 52. As shown in Fig. 4 the opposed arms 42 and 50 of the respective pairs are of substantially identical form.

In order to increase the current controlling ledge 1| (Figs. 1 and 2) the surface of which is capacity and the arc-snuftlng characteristics of the switch mechanism I prefer to employ a pair of substantially U-shaped insulating members 53, one of which is shown in detail in Fig. 6. Members 53 may be formed of any suitable thin and flexible but relatively tough insulating material, the kind sold commercially asiishpaper being preferred. The opposed arms 54 and 55 of each member 53 are preferably of substantially rectangular contour, and slightly wider than the aforementioned arms 42 and 50, as best illustrated in Fig. 1. Said arms are provided adjacent to the upper ends thereof with openings 56 and 51. The contact areas and tips 43, 44 and 5I, 52 are inserted inwardly and upwardly through the respective openings 55, 51, in the manner illustrated in Fig. 4, whereby the contact areas 43, I are` exposed toward the opposite faces of plate I3, and whereby the portions 58 and 59 of said arms are positioned at the rear surfaces Yf the respective contact areas. The lower portions of arms 54 and 55 are therefore adapted to overlie and insulate the inner faces of arms 42 and 50 below said contact areas. Said arms 54 and 55 extend downwardly a substantial distance below the aforementioned ledges, whereby the same are adapted to accommodate therebetween one of the contactors 35 in the off position of the switch shown in Fig. 4. The relatively narrower connecting portions 60 of members 53 are preferably located below the aforementioned shoulders I8 and i9 (Fig. 3) on base I8, said base being recessed as shown to accommodate said connecting portions and the inwardly bent end portions of the arms of contactors 35.

The screw shell contacts 6I of the fuse sockets are preferably of identical form, each being provided with a pair of side openings like that shown at B2 in Fig. 4, whereby the same may selectively accommodate the right-hand or left-hand Wiring terminal members 63, 5.3 of identical form, the terminal portions of which are passed outwardly therethrough prior to insertion of the binding screws 54, 54. Members 53, $3 are adapted for right-hand and left-hand assembly by a mere reversal of one thereof with respect to the other. Each member 63 includes a horse-shoeshaped .portion 55 adapted to overlie and clamp the bottom ange portion of a shell 5I, as shown in Fig. 4, the portions 85 being secured to the bottom walls of recesses 48 and 41 as by means of pairs of screws 65, 86 extending upwardly through base I0. Each member 53 is provided with a pair of laterally extending lugs 81 and 68 angled in opposite directions, the upwardly angled lug 61 of the left-hand terminal and the upwardly angled lug 68 of the right-hand terminal being utilized as the usual wire guards or guides; and the downwardly angled lug 88 of the left-hand terminal and the downwardly angled lug 51 of the right-hand terminal being respectively adapted for engagement with the walls of suitable recesses in base I0 (Fig. 1) to assist in preventing lateral displacement of said terminals. Each terminal 63 is provided with a pair of relatively small circular openings 69 and 10, base I0 being recessed below the opening 89 of the left-hand terminal and below the opening 19 in the right-hand terminal, to provide for insertion and snubbing of the bared ends of branch circuit wires to be clamped by the respective binding screws i4. I Base Ip is likewise recessed to accommodate the shanks (not shown) of said screws 54.

Base III is provided one end thereof with a recessed to accommodate in a substantially flush relation a portion of a fiat metal plate 12. Plate 12 is provided with a tapped opening to accommodate the relatively long shank of a bolt or screw 13 the head of which is located in a countersunk recess in the lower face of base l0; bolt 13 acting to secure plate 12 in position. A plurality of nuts 14 are threaded onto the upstanding shank of screw 13 with lugged washers 15 strung upon said shank below the respective nuts, to provide for attachment of the desired number of neutral circuit wires for grounding thereof. Plate 12 is provided in its outer end with an opening to freely accommodate the shank of a screw 16 which extends downwardly therethrough and takes into a tapped opening in the bottom wall 11 of the sheet metal casing, designated in general by numeral 18, to provide for grounding of plate 12 and the screw 13 associated therewith.

-The bottom wall 11 of casing 18 is provided adjacent to the lower end thereof with a pair of flat-bottomed projections 19 and 89 having openings (not shown) therein to accommodate the shanks of suitable screws,v said bottom wall 11 being also provided at the upper end thereof with a similar perforated boss 3i (Fig. 2) the opening 82 in which is enlarged as indicated at 83 to substantially key-hole form, to provide for downward hooking of boss 8i and opening 32 over the head and shank of a securing screw. The casing 18 may be grounded in any well known manner, as by connecting to ground an armored cable or cable containing the circuit wires leading thereto and/or therefrom.

Casing 18 includes side walls 92 and 83 and end walls 84 (Fig. 2) and 85 (Fig. 3), said side and end walls being integral with the bottom wall 11. Each end wall is provided with a pair of inwardly extending flanges, such as shown at 85 in Fig. 2 and at 81 and 88 in Fig. 3; said flanges lying against the inner faces of the respective side walls and being rigidly attached thereto, as by spot-welding. Said flanges have lugs partially sheared therefrom and bent outwardly at substantially right angles thereto, as shown at 89 (Fig. 2) and at 90 and 9| (Fig. 3); said lugs being located in a common plane adjacent to the open end of casing 18, and each lug having a tapped opening formed therein to accommodate the shank of a cover attaching screw, when covers (not shown) adapted to provide for flush mounting of the casing are employed.

I have shown herein in full lines a cover 94 having a downwardly extending peripheral ange 95 for overlapping engagement with the upper portions of the sidewalls and end walls of casing 18. Flange 95 is provided at one side wall 83 of the casing with horizontally disposed rectangular openings to accommodate a pair of lugs 88 and 91 partially sheared from side wall 83 at the upper edge of the latter and initially bent outwardly to penetrate the aforementioned flange openings, and then bent inwardly, as best shown in Fig. 3 provide a hinge connection between the cover 94 and casing 18. The side Wall 82 of the casing is formed as shown at 98 (Figs. 1 and 3) and cover flange 95 is cooperatively formed as shown. at 99 in Fig. 3 to provide a snap catch for releasabiy retaining the Cover in closed position. The side wall 83 is preferably provided with a pair of outwardly extending bosses |00 and IUI and the respective end walls are provided with one or more outwardly extending bosses, such as shown at |02 in Fig. 2, for cooperative engage?-z ment by the cover ange to insure a rather snug and non-rattling iit of the cover upon the casing. l

Base l0 is rigidly attached to the bottom wall 'il of the casing as by means of a pair of screws |03 and |04 the heads of which are located in recesses in the upper surface of the base and the shanks of which take into tapped openings in said bottom wall. The aforementioned bosses i9, and 8l serve as feet to space the bottom wall of the casing a suicient distance from the surface of the supporting wall or the like to which the complete device is attached, whereby clearance is provided for the Shanks of the aforementioned screws Tli, |03 and |04 (Figs. 2 and 3) below said bottom wall.

The cover memberlid is provided with al de-i pression or recess i415 having therein a slot l il@ to accommodate with .a sliding clearance the aforementioned contactor carrying plate i3. Partially sheared and bent upwardly from cover 04 at one side of slot |06 is a lug |071 having therein an opening |08. Plate 3 is provided with an opening I 09 which is adapted to register with the lug opening |08, when plate i3 is in its inner extreme position, whereby the usual wire may be passed through the alined openings and the wire ends jointly sealed, to prevent unauthorized operation of the switch to circuit completing position. p

As shown in Figs. 2 and 3 plate |3 is provided adjacent to its upper end with a relatively large opening H0 affording a finger grip to facilitate outward pulling of said plate for circuit completion, the aforementioned depression G05 in the cover member affording a good manual grasp upon said plate. Also, as best illustrated in Fig. 3, the upper edge of plate i3 is preferably curved to facilitate a manual downward push,

thereon to dlsengage the contactors from the contacts.

Base l0 is preferably provided at its upper surface with an integral projection H2 (Figs. 1 and 2) which affords a suitable barrier between the adjacent shell contacts 6I of the fuse sockets. Base I0 is also preferably provided with a substantially cylindrical upward projection H3. Projection I I3 is adapted to be rather closely surrounded by the circular wall of an opening H5 provided in a flat resilient insulating plate H4, the contour of which is indicatedin general in dotted lines in Fig. 1, said plate overlying all of the switch contacts and wiring terminal elements of the device to provide a dead-front for the latter. Plate ||4 is of awidth (throughout a portion of its length corresponding to the length of base IIJ) only slightly less than the distance between the side walls 82 and 83 of the casing; whereby when plate ||4 is seated against the upper surface |2 ofthe base, as indicated in dotted lines in'Fig. 1, said side walls of the casing and the projection ||3 cooperate'therewith to prevent substantial movement of plate 14 in its normal plane. As shown in Figs. l and 2, plate H4 is provided with a relatively large substantially elliptical opening H6 to provide clearance for projection H2 and to afford access to the sockets for insertion or removal of fuse plugs.

I provide novel means for releasably retaining plate H4 in assembled position; said means as shown preferably comprising a pair of projections l i1 and I I8 upon the inner surface of side wall d3. Said projections are respectively provided with straight lower edges spaced upwardly from. the

plane of the upper surface l2. of base l0 a distance substantially corresponding to the thickness of plate lill, whereby one side edge of said plate may be inserted or hooked thereunder. The opposite side wall lll? of the casing is provided on its inner surface with a pair of substantially hemispherical bosses il@ and |20, the lower edges of which are likewise located in a plane above the upper surface il. of base l0 a distance substantially corresponding to the thickness of plate M4. After insertion of one side edge of plate M4 beneath projections lll, M8, the other side edge thereof may be forced downwardly over projections M9, l2@ and snapped beneath the lower edges of the latter, a slight degree of bending of plate l ld being necessitated for this purpose, and the same being sumciently resilient to provide for such bending. To remove the-deadfront plate |64 it is only necessary to pull or pry the same upwardly to bend the same suiiiciently to provide for disengagement of the aforementioned edge thereof from the bosses H9, |20.

In practice I prefer to interpose between the bottom face of base l0 and the bottom wall of the casing a relatively thin insulating plate 2| of ber or the like to insure against any possible contact of the aforementioned screws 31 with said bottom wall. Plate I 2| is provided with clearance openings to accommodate the aforementicned shanks of the base securing screws I 03 and |04.

Each of the side and end walls and the bottom wall of casing 18 are provided with two or more knockouts of the triple, double or single-knockout types, certain of said knockouts being illustrated.

What I claim as new and desire to secure by Letters Patent is:

1. In a device of the character described, in combination, a metal casing having bottom, side and end walls and a front opening, a metal cover attached to said casing for closing said front opening, a one-piece insulating base adapted to be produced by a straight-line molding operation, means for removably attaching said base to the bottom wall of said casing, the upper surface of said base being spaced inwardly a substantial distance from the open end of said casing, said base having a plurality of recesses formed therein and opening to said upper surface thereof, a plurality of pairs of center and screw shell fuse socket contacts respectively located within said recesses, two of the center contacts of said fuse sockets having resilient switch contacts formed integrally therewith and arranged in a common vertical plane in laterally spaced relationship to each other, two other switch contacts carried by said base and arranged in opposed -alinement with the respective switch contacts rst mentioned, said base having a passage extending therethrough from frontto rear, a flat plate of insulating material positioned within said passage and continuously -interposed between the respective pairs of opposed switch contacts, said insulating plate extending vertically upwardly from said base and projecting at all times a substantial distance beyond the open end of said casing, said cover having an opening formed therein to provide clearance for said plate during vertical reciprocation of the latter, said plate having openings formed therein, a pair of sheet metal contactors having connecting portions penetrating said openings and arm portions bent to lie against opposite sides of said plate, said contactors being movable jointly into and out of bridging engagement with said pairs of switch contacts upon an outward pull or an inward push upon said plate, and the projecting upper end of said plate being formed to facilitate manual pulling or pushing thereof.

2. In a device of the character described, in combination, a metal casing having bottom, side and end walls and a front opening, a metal cover attached to said casing for closing said iront opening, a one-piece insulating base adapted to be produced by a straight-line molding operation, means -for'removably attaching said base to the bottom wall of said casing, the upper surface of said base being spaced inwardly a substantial distance from the open end of said casing, said base having a plurality of recesses formed therein and opening to said upper surface thereof, va plurality of pairs of center and screw shell fuse socket contacts respectively located within said recesses, two of the center contacts of said fuse sockets having resilient switch contacts formed integrally therewith and arranged in a common vertical plane in laterally spaced relationship to each other, two other switch contacts carried by said base and arranged in opposed alinement with the respective switch contacts first mentioned, said base having a passage extending therethrough from front to rear, a flat plate of insulating material positioned within said passage and continuously interposed between the respective pairs of opposed switch contacts, said insulating plate extending vertically upwardly from said base and projecting at all times a substantial distance beyond the open end of said casing, said cover having an opening formed therein to provide a clearance for said plate during vertical reciprocation of the latter, said plate having openings formed therein, a pair oi sheet metal contactors having connecting portions penetrating said openings and arm portions bent to lie against opposite sides of said plate, said contactors being movable jointly into and out of bridging engagement with said pairs of switch contacts upon an outward pull or an inward push upon said plate, the projecting upper end of said plate being formed to facilitate manual pulling or pushing thereof, said base and said plate having cooperative shoulders formed thereon to limit the degree of inward movement of the latter, said plate having a vertically extending slot ,formed therein, a second insulating plate extending transversely through said slot and rigidly attached to said base for cooperation with the lower end wall of said slot to limit the degree of outward movement of said plate first mentioned, and said second insulating plate cooperating with the vertical walls of said slot to assist guiding said rst mentioned plate in all positions of the latter. f

3. In a device of the4 character described, in combination, a metal casing having bottom, side and end walls and a front opening, a metal cover attached to said casing for closing said vfront opening, a one-piece insulating base adapted to` be produced by a straight-line molding operation, means for removably attaching said base to the bottom wall of said casing, the upper surface of said base being spaced inwardly a substantial distance from the open end of said casing, said base having a plurality of recesses formed therein and opening to said upper surface thereof, a plurality of pairs of center and screw shell fuse socket contacts respectively located within said recesses, two of the center contacts of said fuse sockets having resilient switch contact arms formed integrally therewith and bent to extend upwardly at substantially right angles thereto in laterally spaced relationship to each other, two other switch contact arms carried by said base and arranged in opposed alinement with the respective switch contact 'arms first mentioned, the contact portions of each pair of arms being oiset inwardly toward each other and the tips of said pairs of contact portions being flared apart, a pair of substantially U- shaped iiber members, the arms of said fiber members each having an opening formed therein adjacent to the upper end thereof, the tips and contact portions of said arms being insertable upwardly through said openings whereby each fiber member is interlocked with and restrained against accidental displacement relatively to each opposed pair of contact arms and whereby the lower portions of the arms of said fiber members are positioned on the inner sides of the respective contact arms to provide insulating coverings for the latter, said base having a passage extending therethrough from front to rear, a ilat plate of insulating material positioned within said passage and continuously interposed between the respective pairs of opposed contact portions, said plate having a pair of openings formed therein, a pair of sheet metal contactors having connecting portions penetrating said openings and arm portions bent to lie against opposite sides of said plate, saidv contactors being movable jointly into and out of bridging engagement with said pairs of contact portions upon an outward pull or an inward push upon said plate, and said plate having adjacent to its upper end a iinger opening to facilitate manual pulling thereof and a curved edge to facilitate manual pushing thereof.

4. In a fuseless main switch of the push-pull type, in combination, a -molded insulating base having a passage of substantially rectangular contour in horizontal cross section extending vertically therethrough from iront to rear, the inner end portion of said passage being of reduced dimensions whereby said base is provided with a pair of horizontal shoulders spaced from each other and from the rear surface of said base, a flat plate of insulating material of substantially greater height than said base slidable within said passage, the lower end of said plate being of reduced dimensions to provide a portion adapted to be accommodated by the reduced inner end portion of said passage and to provide spaced shoulders cooperable with said base shoulders to limit the degree of inward movement of said plate, said plate having a relatively long substantially rectangular slot formed therein -at the longitudinal center line thereof and extending from a point adjacent to the lower edge thereof toa plane slightly above the upper surface of said base, when said plate'is in its inner extreme position, a second'at plate of insulating material extending through the slot in said rst plate and rigidly secured to said base,

the lower edge of said second plate being engageable by the lower end wall of said slot to.

limit outwardmovement of said iirst plate relatively to said passage, said second plate also cooperating with thev side walls of said slot to assist in guiding the movements of said first plate, a pair of contactors attached to said rst plate onopposite sides of said longitudinal center line and having portions thereof exposed on opposite faces of said plate, two pairs of resilient stationary contacts carried by said base and into and out of bridging engagement with which the 15 respective contactors are adapted to move upon outward and inward movements respectively of said first plate, and a third at insulating plate secured to the upper surface of said base and overlying said contacts and contactors to pro- .of respectively, the bosses upon one of said side walls having straight lower edges and the bosses vupon the other side wall being of substantially hemispherical form, a iiat plate of resilient insulating material one side edge portion of which is laterally insertable under said straight lower edges and the other side edge portion of which is forcibly insertable under said hemispherical bosses by bending of said plate by pressure applied to the upper surface thereof, said bosses acting to retain said plate fiatwise against the upper surface of said base, said base having an integral portion projecting upwardly from said upper surface thereof and said plate having an opening to accommodate said projecting portion whereby said plate is restrained against substantial movement in its normal plane with respect to said base, said base having a recess opening to the upper surface thereof and said plate and said cover member having openings alined with said recess, a flat insulating actuating plate slidable within said recess and within the openings in said cover member and said plate rst mentioned, the upper portion of said actuating plate projecting at all times a substantial distance above said cover member, the lower portion of said actuating plate having a pair of contactors attached thereto, two pairs of resilient stationary contacts carried by said base, the contacts of each pair being respectively arranged on opposite sides of said recess, said actuating plate being continuously interposed between the respective contacts of said pairs, said contactors being movable by said actuating plate into and out of bridging engagement with said pairs of contacts, and means associated with said base and said actuating plate to limit the degrees of inward and outward movement of the latter.

6. In a fuseless main switch of the push-pull type, in combination, a molded insulating base having a recess opening to the upper surface thereof, said base having a plurality of pairs of ledges located in a common plane, the ledges of each pair being located respectively on opposite sides of said recess in alinement with each other, stationary switch contacts each having a portion secured to one of said ledges and an arm portion bent upwardly at substantially a right angle thereto, each pair of opposed arm portions having contact portions offset toward each other, a pair of relatively thin substantially U-shaped insulating members, the arms of each of said U- shaped members having openings spaced downwardly from the upper ends thereof, the upper ends of said contact arm portions penetrating the respective openings whereby the adjacent contact portions of the former are freed from interference by said U-shaped members, the porgenero? tions of the arms of said U-shaped members below said openings being adapted to overlie the Iadjacent faces of the lower portions of said contact arms to insulate the latter, a flat plate of insulating material vertically slidable within said recess, said plate having a pair of contactors attached thereto for movement'into bridging engagement with the respective pairs of contact portions upon extreme outward movement of said plate, said contactors being also movable by said' plate inwardly from said contact portions and between the insulated lower portions of said contact arms, for the purpose set forth, and said base and-said plate having elements associated therewith to positively limit the degrees of outward and inward movement of the latter.

7. In a fuseless main switch of the push-pull type, in combination, a molded insulating base having, a recess opening to the upper surface thereof, said base having a plurality of pairs of ledges located in a common plane, the ledges of each pair being located respectively on opposite sides of said recess in alinement with each other, stationary switch contacts each having a portion secured to one of'said ledges and an arm "portion bent upwardly at substantially a right angle thereto, each pair of opposed arm portions having contact portions offset toward each other, a pair of relatively thin substantially U-shaped insulating members, the arms of each of said U- shaped members having openings spaced down'- wardly from the upper ends thereof, the upper ends of said contact arm portions penetrating the respective openings whereby the adjacent contact portions of the former are freed from interference by said U-shaped members, the portions of th arms of said U-shaped members below said openings being adapted to overlie the adjacent faces of the lower portions of said contact arms to insulate the latter, a flat plate of insulating material vertically slidable within said recess, said plate having a pair of contactors attached thereto for movement into bridging engagement with the respective pairs of contact portions upon extreme outward movement of said plate, said contactors being also movable by said plate inwardly from said contact portions and between the insulated lower portions of said contact arms, for the purpose set forth, said base and said plate having cooperating shoulders formed thereon to limit the degree of inward movement of the latter, said plate having a longitudinally ext-ending slot formed therein, a second insulating plate extending transversely through said slot and rigidly attached to said base, and the bottom wall of said slot being adapted for cooperative engagement with said second plate to limit the degree of outward movement of the plate first mentioned.

8. In a fuseless main switch of the push-pull type, in combination, a molded insulating base having a recess opening to the upper surface thereof, said base having a plurality of pairs of ledges located in a common plane, the ledges of each pair being located respectively on opposite sides of said recess in alinement with each other,

ends of said contact arm portions penetrating the respective openings whereby the adjacent contact portions of the former are freed from interference by said U-shaped members, the portions of the arms of said U-shaped members below said openings being adapted to overlie,the adjacent faces of the lower portions of said contact arms to insulate the latter, a flat plate of insulating material vertically slidable within said recess, said plate having a pair of contactors attached thereto for movement into bridging engagement with the respective pairs of contact portions upon extreme outward movement of said plate, said contactors being also movable by said plate inwardly from said contact portions and between the insulated lower portions of said contact arms, for the purpose set forth, said base and said plate having cooperating shoulders formed thereon to limit the degree of inward movement of the latter, said plate having a longitudinally extending slot formed therein, a second insulating plate extending transversely through said slot and rigidly attached to said base, the bottom wall of said slot being adapted for cooperative engagement with said second plate to limit the degree of outward movement of the plate rst mentioned, said slotI being spaced upwardly from the lower end of said iirst plate whereby a portion of the latter of substantially rectangular formin transverse cross section is provided, and a resilient metal member in the form of a doubleinclined cam carried by said base, said doubleinclined cam cooperating with said last mentioned portion of said first plate to yieldably resist initial movement of the latter from each of the extreme positions thereof and to assist in eiecting final movement thereof to either of said extreme positions.

9. In a safety switch, in combination, a metal casing having bottom, side and end walls and a front opening, a metal member attached to said casing for closing said front opening, a one-piece molded insulating base rigidly secured to the bottom wall of said casing, the upper surface of said insulating base being spaced inwardly a substantial distance from said front opening, said base having an integral upward projection, a switch mechanism carried by said base and including stationary and movable contact members and wiring terminal elements positioned below said upper surface, the side Walls of said casing having bosses formed on the inner surfaces thereof in a plane slightly above the upper surface of said base, a flat resilient insulating plate having a portion of a width closely approximating the distance between said side walls of the casing and opposite end portions of a width substantially as great as the width of said base and projecting a substantial distance beyond each longitudinal end of the latter, said plate being bendable to provide for movement thereof with a snap action into interlocking engagement with said bosses and into overlapping engagement with the upper surface of said base, said plate having an opening to rather closely accommodate said base projection whereby substantial movement of said plate in its normal plane is positively prevented, said switch mechanism including a reciprocating insulating actuating member projecting upwardly from said base, and said plate and said cover member having alined openings formed therein through which said actuating member extends in all positions of the latter.

10. In a push-pull switch, in combination, a molded insulating base having a recess formed therein and opening to the upper surface thereof, a pair of ledges offset inwardly from the upper surface of said base and arranged in alinement in a common plane on opposite sides of said recess, a pair of stationary contacts having at portions secured to the respective ledges and having resilient arms bent upwardly at substantially right angles to said iiat portions, said arms having alined intermediate portions offset inwardly toward each other to provide contact areas, a substantially U-shaped member formed of flexible insulating material, the arms of said member having alined openings formed therein adjacent to the upper ends thereof respectively, the ends of said resilient contact arms being insertable inwardly and upwardly through the respective openings whereby the portions of said U-shaped member above said openings are positioned exteriorly of said contact arms to provide for exposure ofthe opposed contact areas, the-portions of said U-shaped member below said openings being adapted to overlie the opposed lower portions of said resilient contact arms and extending downwardly a substantial distance below the latter, an actuating member comprising a flat plate of insulating material reciprocable within said recess and continuously interposed between said resilient contact arms, a contactor carried by and having portions thereof exposed on opposite sides of said iiat plate, said contactor being movable upwardly by said plate into bridging engagement with said contact areas, and said contactor being movable downwardly by said plate out of said bridging engagement and between the lower portions of the arms of said U-shaped member to provide for extinguishment of any arcs drawn between said contactor and said contact areas.

11. In a push-pull switch, in combination, a molded insulating base having a recess formed therein and opening to the upper surface thereof, a pair of ledges offset inwardly from the upper surface of said base and arranged in alinement in a common plane on opposite sides of said recess, a pair of stationary contacts having flat portions secured to the respective ledges and having resilient arms bent upwardly at substantially right angles to said flat portions, said arms having alined intermediate portions oiset inwardly toward each other to provide contact areas, a substantially U-shaped member formed of ilexible insulating material, the arms of said member having alined openings formed therein adjacent to the upper ends thereof respectively, the ends of said resilient contact arms being insertable inwardly and upwardly through the respective openings whereby the portions of said U-shaped member above said openings are positioned exteriorly of said contact arms to provide for exposure of the opposed contact areas, the portions of said U-shaped member below said openings being adapted to overlie the opposed lower portions of said resilient contact` arms and extending downwardly a substantial distance below the latter, an actuating member comprising a at plate of insulating material reciprocable within said recess and continuously interposed between said resilient contact arms, a contactor carried by and having portions thereof exposed on opposite sides of said iiat plate, said contactor being movable upwardly by said plate into bridging areas, said contactor being movable downwardly by said plate out of said bridging engagement, said plate having a slot formed therein and exengagement with said contact tending longitudinally to a point adjacent to the lower end thereof, whereby a plate portion of substantially square cross section is provided, a second nat plate extending transversely through said slot and rigidly attached to said base to positively limit the upward movement of said plate rst mentioned, and a resilient metal member in the form of a double-inclined cam atm,-4`

tachcd to said base by said plate second mentioned, said cam cooperating with the portion of said first plate of square cross section, to resist initial movement of said rst plate out of each 'extreme position and to assist in electing the iinal portion of the movement of the latter to each extreme position.

12. In a fuseless main switch of the push-pull type, in combination, a metal casing having! bottom, side and end walls and an open front, a metal cover member attached to said casing for closing said open front, a molded insulating base member secured to the bottom wall of said casing and having a top surface oiset inwardly a substantial distance from said cover member, the side walls of said casing each having bosses formed upon the inner surfaces thereof ina plane a predetermined distance above the upper surface of said base, a flat resilient insulating plate having a width closely approximating the distance between said side walls of the casing and a length at least as great as the length of said base, said plate being bendable to provide for movementthereof with a snap action into or out of interlocking engagement with said bosses and into or out of overlapping engagement with the upper surface of said base, said base having an integral upward projection and said plate having an opening to rather closely accommodate said projection whereby substantial movement of said plate in its normal plane is positivelyprevented, a switch mechanism carried by said base and including stationary and mov- `able contact members'and wiring terminal elements positioned below the upper surface of said base, said switch mechanism including a reciprocating insulating actuating member by which the movable cont'act member is carried, said plate and said cover member-having alined openings formed therein through which s'aid actuating member extends in all positions of the latter, said covermember having a perforated upright lug thereon at one side of the aforementioned opening in the former, and said actuating member having an opening adapted for alinement with said lug perforation in the inner extreme position of the former,v to provide for'securement vof said parts in a iixed relation as by means of a sealing Wire of usual form.

13. In a device of the character described, in combination, a metal casing having bottom, side and end walls and a front opening, a metal cover attached to said casing for closing said front opening, a one-piece molded insulating base, means for removably attaching said base to said casing, a resilient stationary switch contact supported by said base and arranged in a vertical plane, another switch contact carried by said base and arranged in opposed alinement with the switch contact first mentioned, said base having a recess formed therein between said switch contacts and opening tothe upper Surface thereof, a push-pull insulating member positioned within said recess and continuously interposed between the switch contacts, said member extending vertically upwardly from said base and vprojecting at all times beyond the open end of ,ported by said base and said casing, said cover having an opening formed therein to provide clearance for said member during vertical reciprocation of the latter, said member having an opening extending transversely therethrough, a metal contactor having a portion penetrating said opening and contact portions exposed on opposite sides of said member, said contactor being movable into and out of engagementl with said switch contacts upon an outward pull or an inward push upon said member, and the projecting upper end of said member being formed to facilitate manual pulling or pushing thereof.

14. In a device of the character described, in combination, a metal casing having bottom, side and end walls and a front opening, a metal cover attached to said casing for closing said front opening, a one-piece molded insulating base, means for removably attaching said base to said casing, a resilient stationary switch contact suparranged in a vertical plane, another switch contact carried by said base' and arranged in opposed alinement with the switch contact rst mentioned, said base having a recess formed therein between said switch contacts and o ening to the upper surface thereof, a push-pull insulating 'member positioned within said recess and continuously interposed between the switch contacts, said member extending vertically upwardly from said base and projecting at all times beyond the open end of said casing, a substantially U-shaped element formed of exible insulating material, the arms of said element having alined openings formed therein adjacent to the upper ends thereof respectively, the ends of said resilient stationary contacts being insertable inwardly and upwardly through the respective openings whereby the portions of the arms of said element above said openings are positioned exteriorly of said stationary contacts to provide for exposure of portions of the opposed inner surfaces of the latter, the portions of the arms of said element below said openings being adapted to overlie the opposed lower portions of said stationary contacts and extending a substantial distance' below the latter, for the purpose set forth, said cover having an opening formed therein to provide clearance for said member during vertical reciprocation of the latter, said member having an opening extending transversely therethrough, a metal contactor having a portion penetrating said opening and contact portions exposed on opposite sides of said member, said'contactor being movable into and out of engagement with said switch contacts upon an outward pull or an inward push upon said member, and the projectlng upper end' of said member being formed to facilitate manual pulling or pushing thereof.

15. In a front-operated safety switch of the multi-pole type, in combination, a metal casing having bottom, side and end walls and a front opening, a metal cover attached to said casing for closing said front opening, a one-piece insulating base, means for removably attaching said base to said casing, a plurality of sets of fuse contacts carried by said base, one fuse contact of each set having a resilient switch contact electrically connected therewith and extending upwardly therefromr in a plane at right angles thereto, a plurality of other switch contacts carried by said base and arranged in opposed alinement with the respective switch contacts rst mentioned, said base having a recess formed therein between said pairs of opposed switch contacts and opening to the upper surface thereof, a one-piece manual push-pull insulating member positioned within said recess and continuously interposed between said pairs of switch contacts, said member extending vertically upwardly from said base and projecting at all times beyond the open end of said casing, said cover having Aan opening formed therein to provide clearance for said member during vertical reciprocation of the latter, said member having a plurality of openings formed therein, a plurality of metal contactors having portions penetrating said openings and contact portions exposed on both sides of said member, said contactors being movable into and out of engagement with said switch contacts upon an outward manual puli or an inward manual push directly upon said member, the projecting upper end of said member being provided with a relatively large opening to facilitate such manual pulling or pushing thereof, and cooperating means carried by said insulating member and said base to positivelyV limit the degrees of outward and inward movement of the former.

16. In a front-operated safety switch of the multi-pole type, in combination, a. metal casing having bottom, side and end walls and a front opening, a metal cover attached to said casing for closing said front opening, a. one-piece molded insulating base, means for removably .attaching said base to saidroasing, said base having a plurality of substantially cylindrical recesses formed therein and opening to the upper surface thereof, center and screw shell fuse socket contacts located Within each of said recesses, the center contacts .of said fuse sockets having resilient switch contacts electrically connected therewith and extending upwardly therefrom in a plane at right angles thereto, other switch contacts carried by said base and arranged in opposed alinement with the switch contacts ilrst mentioned, said base having another recess formed therein and opening to the upper surface thereof, a oneplece manual push-pull insulating member positioned within said last mentioned recess and continuously interposed between said opposed pairs of switch contacts, said member extending vertically upwardly from said base and projecting at all times beyond the open end of said casing, said cover having an opening formed therein to provide clearance for said member during vertical reciprocation of the latter, said member having a plurality of openings formed therein, metal contactors each having a portion penetrating one of said openings and contact portions exposed on opposite sides of said member, said contactors being movable into and out of bridging engagement with the respective opposed pairs of switch contacts upon an outward manual pull or an inward 'manual push directly upon 4said member, the projecting upper end of said member being formed to facilitate such manual pulling or pushing thereof, and cooperating means carried by said insulating member and said base to positiverigidly secured tothe bottom wall oi' said casing and having a top surface offset inwardly a substantial distance fromsaid cover member, a relatively thin, at plate of insulating material engaged with certain of said casing walls and overlying the upper surface of said base, a pushpull switch mechanism carried by said base and including a plurality of sets of stationary and movable contact members and wiring terminal elements positioned below the upper surface of said base, said switch mechanism including a reciprocatinginsulating actuating member by which the movable contact members are carried, said plate and said cover member having alined openings formed therein through which said actuating member extends in all positions of the latter, a plurality of sets of fuse contacts carried by said base and respectively associated with ysaid sets of switch contacts, said plate being formed to provide access to said fuse' contacts when the former is in assembled relation to said base, said cover member having a perforated upright lug formed integrally therewith at one side of the aforementioned opening in the former, and said actuating member having an opening adapted for alinement with said lug perforation in the inner extreme position o1 the former, to provide for securement of said parts in a xed relation as by means of a sealing wire or the like.

18. In a push-pull switch, in combination, a molded insulating base having a recess formed therein and opening to the upper surface thereof, a pair of ledges oiset inwardly from the upper surface of said base and arranged in alinement in a common plane on opposite sides of said recess, a pair of stationary contacts having flat portions secured to the respective-ledges and having resilient arms bent upwardly at substantially right angles to said at portions, said arms having alined intermediate portions oilset inwardly toward each other to provide contact areas, a substantially U-shaped member formed of flexible insulating material, the arms of said member having alined openings formed therein adjacent to the upper ends thereof respectively,

the ends of said resilient contact arms being insertable inwardly and upwardly through the respective openings whereby the portions of said U-shaped member above said openings are positioned exteriorly of said contact arms to provide for exposure of-the opposed contact areas, the portions of said U-shaped member below said openings being adapted to overlie the opposed lower portions of said resilient contact arms and extending downwardly a substantial distance below the latter, an actuating member comprising a i'lat plate of insulating material reciprocable within said recess and continuously interposed between said resilient contact arms,'a contacter carried by and having portions thereof exposed on opposite sides of said at plate, said contactor being movable upwardly by said plate into bridging engagement with said contact areas, said contactor being movable downwardly by said plate out of said bridging engagement, and a re- 

